SEMICONDUCTOR LASER

• US 20090022195A1
• Filed: 03/15/2006
• Published: 01/22/2009
• Est. Priority Date: 04/13/2005
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kuramoto, Kyosuke
• Granted Patent: US 7,643,527 B2
• Time in Patent Office: Days
• US Class Current: 372/45.10
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/0021 Degradation or life time measurements
• CPC Class Codes: H01S 5/0202 Cleaving
• CPC Class Codes: H01S 5/0206 Substrates, e.g. growth, shape, material, removal or bonding; specific crystal orientation H01S5/3202
• CPC Class Codes: H01S 5/0237 by soldering
• CPC Class Codes: H01S 5/04254 characterised by the shape
• CPC Class Codes: H01S 5/04256 characterised by the configuration
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/2214 based on oxides or nitrides
• CPC Class Codes: H01S 5/2231 with inner confining structure only between the active layer and the upper electrode
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

A semiconductor laser having a high electrostatic withstand voltage, resistant to a power supply surge, and having improved long-term reliability is obtained by reducing current leakage through a threading dislocation portion. The semiconductor laser includes a substrate having a high dislocation region having a dislocation density of 1×10⁵ cm⁻² or more, a crystalline semiconductors structure located on the substrate and having an active layer, an insulating film located on the semiconductors structure, a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer, and a back electrode located on a rear surface of the substrate. The semiconductor laser has a laser resonator with a length L, and the area of the surface electrode is 120×L μm² or less.

Claims

1. A semiconductor laser comprising:

a substrate having a high dislocation region having a dislocation density of at least 1×

10⁵ cm<sup>−

2</sup>;

a crystalline semiconductor structure located on the substrate and having an active layer;

an insulating film located on the semiconductor structure;

a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer; and

a back electrode located on a rear surface of the substrate, wherein

the semiconductor laser includes a laser resonator having a length L, and

the surface electrode has an area not exceeding 120×

L μ

m².

2. The semiconductor laser according to claim 1, wherein the area of the surface electrode does not exceed 80×

L μ

m².

7. The semiconductor laser according to claim 1, further comprising a surface dummy electrode located on the insulating film, and through which no current flows.

15. The semiconductor laser according to claim 1, wherein the substrate is GaN.

3. A semiconductor laser comprising:

a substrate having a high dislocation region, and which has a stripe shape;

a crystalline semiconductor structure located on the substrate and having an active layer;

an insulating film located on the semiconductor structure;

a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer; and

a back electrode located on a rear surface of the substrate, wherein

the semiconductor laser includes a laser resonator having a length L, and

a first region within 100 μ

m from a center of the high dislocation region, on opposite sides of the high dislocation region, in the surface electrode, has an area not exceeding 60×

L μ

m².

4. The semiconductor laser according to claim 3, wherein the area of the first region does not exceed 45×

L μ

m².

16. The semiconductor laser according to claim 3, further comprising a surface dummy electrode located on the insulating film, and through which no current flows.

5. A semiconductor laser comprising:

a substrate having a high dislocation region, and which has a stripe shape;

a crystalline semiconductor structure located on the substrate and having an active layer;

an insulating film located on the semiconductor structure;

a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer; and

a back electrode located on a rear surface of the substrate, wherein

the semiconductor laser includes a laser resonator having a length L, and

a first region within 60 μ

m from a center of the high dislocation region, on opposite sides of the high dislocation region, in the surface electrode, has an area not exceeding 20×

L μ

m².

6. The semiconductor laser according to claim 5, wherein the area of the first region does not exceed 15×

L μ

m².

17. The semiconductor laser according to claim 5, further comprising a surface dummy electrode located on the insulating film, and through which no current flows.

8. A semiconductor laser comprising:

a substrate having a high dislocation region, and which has a striped shape;

a crystalline semiconductor structure located on the substrate and having an active layer;

an insulating film located on the semiconductor structure;

a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer; and

a back electrode located on a rear surface of the substrate, wherein

the semiconductor laser includes a laser resonator having a length L, and

the back electrode does not exceed 140×

L μ

m².

9. The semiconductor laser according to claim 8, wherein the area of the back electrodes does not exceed 100×

L μ

m².

14. The semiconductor laser according to claim 8, further comprising a back dummy electrode located on the rear surface of the substrate, and through which no current flows.

10. A semiconductor laser comprising:

a substrate having a high dislocation region, and which has a stripe shape;

a crystalline semiconductor structure located on the substrate and having an active layer;

an insulating film located on the semiconductor structure;

a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer; and

a back electrode located on a rear surface of the substrate wherein

the semiconductor laser includes a laser resonator having a length L, and

a first region within 100 μ

m from a center of the high dislocation region, on opposite sides of the high dislocation region, in the back electrode, has an area not exceeding 80×

L μ

m².

11. The semiconductor laser according to claim 10, wherein the area of the first region does no exceed 65×

L μ

m².

18. The semiconductor laser according to claim 10, further comprising a back dummy electrode located on the rear surface of the substrate, and through which no current flows.

12. A semiconductor laser comprising:

a substrate having a high dislocation region, and which has a stripe shape;

a crystalline semiconductor structure located on the substrate and having an active layer;

an insulating film located on the semiconductor structure;

a surface electrode located on the insulating film and electrically continuous with the semiconductor structure for injection of a current into the active layer; and

a back electrode located on a rear surface of the substrate, wherein

the semiconductor laser includes a laser resonator having a length L, and

a region within 60 μ

m from a center of the high dislocation region, on opposite sides of the high dislocation region in the back electrode, has an area not exceeding 40×

L μ

m².

13. The semiconductor laser according to claim 12, wherein the area of the first region does not exceed 25×

L μ

m².

19. The semiconductor laser according to claim 12, wherein the substrate is GaN.